MAX1987

19-2559; Rev 0; 7/02 PRELIMINARY Dual-Phase, Quick-PWM Controllers for IMVP-IV CPU Core Power Supplies CONFIDENTIAL INFORMATION—RESTRICTED TO INTEL IMVP LICENSEES General Description The MAX1987/MAX1988 are dual-phase, Quick-PWM™, step-down controllers for IMVP-IV™ CPU core supplies. Dual-phase operation reduces input ripple current requirements and output voltage ripple, while easing component selection and layout difficulties. The QuickPWM control scheme provides instantaneous response to fast load-current steps. The MAX1987/MAX1988 include active voltage positioning with adjustable gain and offset, reducing power dissipation and bulk output capacitance requirements. The MAX1987/MAX1988 are intended for two different notebook CPU core applications: stepping down the battery directly or stepping down the 5V system supply to create the core voltage. The single-stage conversion method allows these devices to directly step down highvoltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down the 5V system supply instead of the battery) at higher switching frequency provides the minimum possible physical size. The MAX1987/MAX1988 meet the IMVP-IV specifications and can directly interface with the CPU powergood signals from the VCCP and VCCMCH rails within the system. The switching regulator features power-up sequencing, automatically ramping up to the Intelspecified boot voltage. The MAX1987/MAX1988 also feature independent four-le...